The prevention of preterm birth with the use of antibiotics

Infection is a well recognised cause of spontaneous early preterm labour. Preterm labour of infective aetiology is refractory to the use of tocolytic agents and affected women have a higher risk of subsequent chorio-amnionitis and neonatal infection. Antibiotics used prophylactically for the prevention of preterm labour are more likely to be successful if given systemically. Intravaginal antibiotics are only likely to be of benefit if they are used early in the second trimester and in those women in whom there is full expression of abnormal genital tract flora (grade III bacterial vaginosis on Gram stain of vaginal secretions). Antibiotic treatment for women far removed from term offers significant benefit with respect to pregnancy prolongation. The value of extended antibiotic treatment is unclear since this may lead to the development of resistant bacterial strains.

The evidence with respect to the use of antibiotics for women in preterm labour is inconsistent though there is a trend toward benefit.